Direct comparison of photoluminescence lifetime and defect densities in ZnO epilayers studied by time-resolved photoluminescence and slow positron annihilation techniques

被引：25
作者：
Koida, T
Uedono, A
Tsukazaki, A
Sota, T
Kawasaki, M
Chichibu, SF [1 ]
机构：
[1] Univ Tsukuba, Inst Phys Appl, Tsukuba, Ibaraki 305, Japan
[2] Univ Tsukuba, Grad Sch Pure & Appl Sci, Tsukuba, Ibaraki 305, Japan
[3] JST, ERATO, NICP, Tokyo 1020071, Japan
[4] Tohoku Univ, Inst Mat Res, Sendai, Miyagi 9808755, Japan
[5] Waseda Univ, Dept Elect Engn & Biosci, Tokyo 1698555, Japan
[6] COMET, Tsukuba, Ibaraki 3050044, Japan
[7] RIKEN, Photodynam Res Ctr, Sendai, Miyagi 9800868, Japan
来源：
PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE | 2004年 / 201卷 / 12期
关键词：
D O I：
10.1002/pssa.200405035
中图分类号：
T [工业技术];
学科分类号：
08 ;
摘要：
The roles of point defects and defect complexes governing nonradiative processes in ZnO epilayers were studied using time-resolved photoluminescence (PL) and slow positron annihilation measurements. The density or size of Zn vacancies (V-Zn) decreased and the nonradiative PL lifetime (tau(nr)) increased with higher growth temperature for epilayers grown on a ScAlMgO4 substrate. Accordingly, the steady-state free excitonic PL intensity increased with increase in tau(nr) at room temperature. The use of a homoepitaxial substrate further decreased the V-Zn concentration. However, no perfect relation between tau(nr) and the density or size of V-Zn or other positron scattering centers was found. The results indicated that nonradiative recombination processes are governed not solely by single point defects, but by certain defect species introduced by the presence of V-Zn such as vacancy complexes.
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页码：2841 / 2845
页数：5
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